A ball of lead 4 cm in diameter is covered with gold. If the volume of the gold and lead are equal, then the thickness of gold (given cube root 3= 1.259) is approx... Vol of LEAD = vol of GOLD d^3 = D^3 - d^3 2d^3 = D^3 ==> D^3=>2* 64 = 128 D = 5.036 , now Thickness of gold ==> D - d /2==> 5.036 - 4/2 => 0.518